“You could have [guessed] my diet based on [which chain restaurant] had the biggest billboard,” says Jillette, who lives in Las Vegas with his wife, Emily, and their two children, daughter Moxie, 11, and son Zolten, 10.

His eating showed no sign of slowing down.

It took a toll on his health.

He weighed 334 pounds at his recent heaviest, was on six different blood-pressure medicines — “they were all at the highest doses available” — and in October 2014 had surgery for a heart blockage.

That was when his doctor suggested gastric bypass surgery to reduce his girth and curtail overeating.

But Jillette didn’t want to go that route. “The measurement was so extreme that it gave me license to do something crazy [in order to avoid it],” he tells The Post.

He wasn’t sure what that crazy thing would be until running into Ray Cronise, a former NASA scientist who is writing a book called “Our Broken Plate.”

Cronise, who visited Jillette backstage in Vegas, had been on an eating plan bereft of animal products, sugar, oil and flour.

Cronise also told him about a water fast he had been on, a potato plan he experimented with, and a glucose monitor inserted under his skin.

Jillette, who had lost only 15 pounds until that point on a conventional diet, wanted in.

“I asked Penn to make a major lifestyle transformation and to interrupt his current relationship with food,” Cronise tells The Post.

He made the magician take cold showers and encouraged extended periods of sleep and fasting to trigger a “metabolic winter.” The idea was that it would goose the body into using nutritional reserves to bring on weight loss.

And exercise was forbidden: “It puts an additional nutritional load on his body, and he may not be getting that nutrition,” says Cronise.

“Why would you want somebody 100 pounds overweight to risk injury by exercising?”

potato diet ?!

Phase 1 of the diet — which removed sociable fun from eating and eliminating salt and sugar addictions — allowed Jillette to have as many potatoes as he wanted.

Fingerlings, russets, Yukon Gold and Japanese sweet potatoes were all fair game. They could be consumed baked, boiled or even raw.

Jillette needed to eat the entire potato, skin and all. There could be no salt or oil or sour cream. Nothing but potatoes — and he’d eat about five of them per day.

Cronise says he could have chosen one of any number of foods, but that he settled on the potato because of its healthfulness.

“People think of it as a carbohydrate, but for a lot of the planet it serves as a protein source.”

After 14 days of eating nothing but potatoes, in December 2014, Jillette dropped 18 pounds. At that point, he was allowed to enjoy corn. “It tasted like candy,” he recalls, adding that, over time, Cronise worked in other vegetables, fruits and unrefined grains.

Jillette thrived on the diet’s rigidity, dropping another 72 pounds by March 2015. “I fail at things that are not black- and-white,” he says. “Introduce shades of gray and I f–k up.”

THEN: 334 lbs. Photo: AP

But the diet may not be for everyone, something the 6-foot-7 magician underscores in his book.

And it’s certainly not a plan advised by weight-loss professionals.

“I would not recommend eating only potatoes,” says Manhattan-based registered dietitian Keri Glassman. “In being so restrictive, most people get set up for failure.”

Jillette was especially worried about going off the rails on cheat days, which Cronise says is a far better alternative to going off the diet a little bit every day.

“I thought I’d either get really sick or love it so much that I couldn’t go back” to dieting, Jillette says.

“I went out for hamburgers, onion rings, bread and butter, chocolate mousse cheesecake — a total feast. And what’s amazing is that neither of those two things happened.

The food tasted good, but not great. Before bed, I had a little indigestion.”

Jillette now enjoys a cheat day every two weeks. He found his disposition dramatically improved, his blood pressure lowered and his energy increased for running around with his kids.

Since hitting his target weight of 229 pounds last year, he’s managed to keep it off. He began doing cardio and weight-training and remains committed to eating large quantities of fruits and vegetables.

“I eat no animal products and no refined grains,” he says.

These days, he subsists on just one meal a day: often a giant salad eaten at 5 p.m., plus enormous quantities of fruit.

“I get tired of chewing before I get too many calories,” he says.

-------

While Jillette is a fan of the diet, one thing he does not do is try to get other heavyweights to start eating tubers.

*Nothing in this website is intended to diagnose, prescribe or substitute for medical or professional advice. This website is provided as a service, to help educate you on possible options for healing. You are encouraged to discuss your options with your own health care provider. AlternativeWaysToHeal.com is not responsible for any harm or loss caused by reliance on any information found on this site.